The invention pertains to systems for the management and routing of optical fiber cables.
In the telecommunications industry, the use of optical fibers for signal transmission is accelerating. With the increased utilization of optical fiber systems, optical fiber cable management requires industry attention.
On area where optical fiber management is necessary is the routing of optical fibers from one piece of optical fiber equipment to another. For example, in a telecommunications facility, optical fiber cables may be routed between fiber distribution equipment and optical line terminating equipment. In buildings and other structures which carry such equipment, the cable routing can take place in concealed ceiling areas or in any other manner to route cables from one location to another.
When routing optical fibers, it is desirable that any routing system will be readily modifiable and adaptable to changes in equipment needs. Accordingly a routing system is not practical which would require a high capital outlay and which could not be readily adapted to changes in a customer""s needs. Namely, if routing paths, once established, are forever fixed, the system cannot adapt. Also, and perhaps most important, any routing system must protect optical fibers from damage. In the use of optical fibers, it is recognized that the fibers should not bend beyond a minimum radius of curvature. For example, it is commonly recognized that optical fibers should not be bent in a radius of less than 1.5 inches. U.S. Pat. No. 5,937,131 discloses an optical cable exit trough addressing some of these concerns, however, there remains room for improvement. Specifically, when cable troughs are placed near ceiling areas, an exit trough mounted thereto may not fit between the cable trough and the ceiling or ceiling fixtures such as light fixtures. Therefore, there is a need for lower profile exit troughs which still maintain the minimum bend radii required to protect the system cables.
According to preferred embodiments of the present invention, a cable routing system is disclosed for routing optical fiber cables between optical transmission equipment. The system includes a lateral trough configured for defining a cable pathway. The lateral trough typically includes a planar upstanding side with a top end. An exit trough according to the present invention is mountable to the lateral trough to provide a cable exit pathway from the lateral trough. The exit trough includes an arch-wall having an upper convex surface and a lower concave surface, and a sidewall portion. The sidewall portion is positionable inside the lateral trough so that the arch-wall is not extending tangentially from the upstanding side. The arch-wall instead crosses the plane occupied by the upstanding side in a non-tangent direction adjacent the top edge, such as at an angle greater than or equal to 15 degrees. The arch-wall protects the cable from the top edge of the lateral trough. The sidewall portion extends into the interior of the lateral trough sufficient to provide cable protection of cables extending from the lateral trough to the exit trough.
The exit trough includes a projecting member extending from the concave surface of the arch-wall and spaced from the sidewall portion of the arch-wall to receive between the sidewall portion and the projecting member a portion of the upstanding side of the lateral trough adjacent to the top edge of the lateral trough. An exit trough portion extends from a middle of the sidewall portion in a direction away from the lateral trough. The exit trough portion is defined by a convexly curved surface of the arch-wall as well as two convexly curved upstanding side surfaces on opposite sides of the bottom trough surface.
The exit trough defines a cable pathway leading upwardly and away from the lateral trough. By crossing the plane of the upstanding side of the lateral trough at an angle adjacent the top edge instead of exiting tangentially, the exit trough maintains a lower profile, allowing for ease of use near ceilings and ceiling fixtures. The exit trough is mountable to the lateral trough without modification to the lateral trough. The exit trough can be placed generally at any location along the lateral trough, and can be placed during initial system setup, or at a later time as the need arises for an exit pathway from the lateral trough, such as when new optical transmission equipment is added to the system. The exit trough may include a downspout portion defining a downwardly directed cable pathway, or other directional pathway as desired.
In one preferred embodiment the exit trough includes curved cable guide walls at opposite ends of the sidewall portion. The curved cable guide walls assist in guiding the cables into the exit trough from the lateral trough without bending the cables beyond their minimum bend radius.
In another preferred embodiment of the present invention, the sidewall portion is curved at opposite ends to meet an interior surface of the upstanding wall of the lateral trough.